At present, numerous therapeutic techniques involve the systemic delivery of one or more therapeutic agents or the systemic removal of an undesirable chemical entity. Systemic delivery and removal techniques, however, are not well suited to all therapies.
For instance, systemic delivery requires exposing sites other than the site of interest to a therapeutic agent. Indeed, large quantities of therapeutic agent within the entire system are often required to obtain the desired effect at a desired site. As a result, the therapeutic agent concentration at the site of interest is often limited by the detrimental effects of the agent at sites remote from the site of interest.
Systemic delivery techniques are also commonly undesirable in that the therapeutic agent is degraded and eliminated by an organ system(s) remote from the site of interest.
Systemic removal techniques are also frequently undesirable, because a chemical entity that is undesirable at one specific site may be useful, or even essential, at another site.
The above problems can be avoided by techniques in which a therapeutic agent is locally provided at a site of interest or an undesirable chemical entity is locally removed from a site of interest.
In response to this recognition, techniques and articles for the localized delivery of therapeutic agents to bodily tissue, and for the localized removal of undesirable chemical entities from bodily tissue, have been developed.